Children ask many questions, but the role these questions play in the child's cognitive development has gone largely unexplored. The goat of the current research is to investigate the questions children ask, what role these questions play in cognitive development, and what they can tell us about children's cognitive structures; particular emphasis will be on the acquisition of biological knowledge. The first set of studies will record and analyze children's questions gathered from (a) a diary study, (b) conversation as children walk through a zoo with their parents, and (c) 5 corpora in the CHILDES database. The second set of studies will explore the child's ability to resolve ambiguous or conflicting information by asking questions, using a 20-questions style game, and using a procedure that engages children in an ambiguous task. The third set of studies will explore any privileged role played by information obtained in response to questions by testing children's retention of information received in response to questions vs. information not preceded by a question (both while learning a game), and by testing retention of information that has previously been found to be of interest to children the same age (shown by their questions) vs. other information. Exploration of these issues will make important contributions to the long-form understanding of how children's conceptual development proceeds.